OBJECTIVES: 1. Production and characterization monoclanal antibodies (Mab) reacting with allotypes, idiotypes and B cell surface markers. 2. Mab analysis of IgH polymorphisms (allotypes and idiotypes): a. Definition of new alleles (allotypes); b. Definition and linkage of new IgCH loci; c. Identification of Ig VH polymorphisms (idiotypes). 3. Two-dimensional gel analysis of mouse Ig polymorphism and heterogeneity: a. Chain composition and monoclonality of Mabs; b. Definition and linkage of new IgCH loci. 4. Characterization of Ig and other surface markers on B cells at successive stages during differentiation. 5. Development and study of IgH congenic strains. 6. Ig regulatory abnormalities in congenic strains: a. analysis of "paraproteins" produced by SJL and SJL.Iga congenic mice; b. Induction of allotype suppression by perinatal exposure to anti allotype antiserum: isotype requirements; c. "Constitutive" suppression of IgG production in BALB/c.Igb (BAB/14) mice.